The present invention relates to a collapsible squeeze tube for housing cream-like substances, such as foodstuffs and toothpaste, therein, and in particular to an improvement of such a tube with a blank cap which includes a body made by turning a laminated aluminium sheet provided with a synthetic resin film on opposite sides thereof into a cylindrical body, the body being provided with a synthetic resin head which includes a mouth member and a shoulder member which are integrally molded, and the mouth member is closed with a thin sheet member, connected to the upper end thereof.
A conventional method of making a collapsible squeeze tube, in which a body of the tube is made by turning a laminated aluminium sheet provided with a synthetic resin film on opposite sides thereof into a cylindrical body, the body being provided with a synthetic resin head, wherein a mouth member and a shoulder member are integrally molded, connected to the upper end thereof, has been widely used in the manufacture of a squeeze tube. However, with such a tube, since the head is formed of a single synthetic resin material, it is impossible to simultaneously make the tube both highly gas tight (gas impermeable) and highly waterproof. Normally a synthetic resin material is wanting in either waterproofness or gas tightness.
Accordingly, in order to assure high degrees of both gas tightness (gas impermeability) and waterproofness, means as shown in FIG. 3 has been proposed. In particular, a laminated aluminium sheet 6 provided with a polyolefin type synthetic resin film laminated on both sides thereof is molded from a push die 8 in a drawing manner along the internal surface of a head 7 (the internal surface of a shoulder member 7a and a mouth member 7b of the head 7), whereby the head is covered all over the internal surface thereof and at the same time a blank cap 9 is formed.
However, with the tube formed by the abovedescribed prior method there has been the possibility that the synthetic resin film layer may be damaged due to an abnormal extension and bending in the process of drawing and pressing the laminated aluminium sheet 6 to the internal surface of the head, whereby this metallic layer is subjected to corrosion causing it to lose its gas tightness, and to the pin hole phenomenon (the phenomenon where holes, which seem to be broken through with a pin point, are generated) since the blank cap portion is also extended by the drawing process.
With this prior method, there is also the following important problem: Since the laminated aluminium sheet is extended by a drawing process, it is necessary to form the synthetic resin film to be laminated on the laminated aluminium sheet, of extensible polyolefin type synthetic resin materials. Thus, polyethylene and the like have usually been used. However, polyethylene has a poor adherence to aluminium and it is partially stripped during extension even though adhesives are used according to circumstances. In addition, there is the possibility that the comparatively highly penetrative contents filling the tube may penetrate the resin film layer to chemically act upon the boundary surface of the resin film layer and the aluminium surface, thereby remarkably reducing the adhesion strength, or stripping the resin film layer. When this stripping phenomenon occurs on the lower surface of the blank cap 9, or the resin film layer is brought into a condition of being liable to strip, since the lower film layer 9a is pushed down by a projection member 10, as shown in FIG. 4, the blank cap 9 cannot be broken through by the projection member 10.
Thus, it is a main object of the present invention to provide a squeeze tube with a blank cap which can solve the problems of the conventional tube.